vmupdate: answer "yes" to the import key question

When fetching repository metadata for the first time, dnf will ask for
confirmation on importing metadata signing key. Since the key is
imported from the local filesystem, it's safe to do, so do it
automatically.

QubesOS/qubes-issues#9807

Author: marmarek

vmupdate/agent/source/dnf/dnf_cli.py

@@ -53,6 +53,7 @@ def refresh(self, hard_fail: bool) -> ProcessResult:
         cmd = [self.package_manager,
                "-q",
                "check-update",
+               "--assumeyes",
                f"--setopt=skip_if_unavailable={int(not hard_fail)}"]
         result_check = self.run_cmd(cmd)
         # ret_code == 100 is not an error